The present invention relates to an electrode-incorporating separator, which is incorporated inside the separator, an electrical storage device, and a vehicle.
As is conventionally known, a rechargeable secondary battery is reusable and generally employed in various apparatuses and devices. In the field of vehicles, reduction of use of fossil fuel and decrease of carbon dioxide emission are demanded. As a result, vehicles driven by motors using such secondary batteries as power sources, including hybrid vehicles and electric vehicles, are now widely used. The secondary batteries are demanded to be rechargeable/dischargeable by high-current and have a high capacity. For example, lithium ion secondary batteries are mass-produced as finished products.
As this type of secondary batteries, secondary batteries having a laminated structure, for example, are publicly known. One such secondary battery includes an electrode assembly formed by alternately laminating a positive electrode sheet, a negative electrode sheet, and a separator for insulating the sheets from each other. However, since the laminated structure is manufactured through steps of sequentially laminating the positive electrode sheet, the negative electrode sheet, and the separator, a large number of laminating steps are necessary. This prolongs the takt time for manufacturing the secondary battery and decreases productivity. To solve this problem, a technique has been proposed in which the number of the laminating steps is decreased to improve the productivity of batteries by, for example, incorporating a positive electrode sheet in a bag-like separator in advance (see Patent Document 1).
It is desired that such types of separators have improved durability against, for example, heat shrinkage. To obtain the improved durability, it has been proposed to coat a surface of a separator using a certain coating material (for example, a ceramic). However, if the bag-like separator is formed by joining a separator body having a surface coated with coating material such that the separator body has a bag-like shape, the coating material applied onto the surface of the separator body may hamper desirable joining of the separator body, thus making it difficult to form the bag-like separator in an appropriate manner.